Physiology, Glucose Metabolism

Excerpt

Glucose is central to energy consumption. Carbohydrates and proteins ultimately break down into glucose, which then serves as the primary metabolic fuel of mammals and the universal fuel of the fetus. Fatty acids are metabolized to ketones. Ketones cannot be used in gluconeogenesis. Glucose serves as the major precursor for the synthesis of different carbohydrates like glycogen, ribose, deoxyribose, galactose, glycolipids, glycoproteins, and proteoglycans. On the contrary, in plants, glucose is synthesized from carbon dioxide and water (photosynthesis) and stored as starch. At the cellular level, glucose is usually the final substrate that enters the tissue cells and converts to ATP (adenosine triphosphate).

ATP is the energy currency of the body and is consumed in multiple ways, including the active transport of molecules across cell membranes, contraction of muscles and performance of mechanical work, synthetic reactions that help to create hormones, cell membranes, and other essential molecules, nerve impulse conduction, cell division and growth, and other physiologic functions.